A multi-million pound scheme to cut journey times and increase train services between Chester and Wrexham has hit the buffers.
The project, costing nearly £40m, was scheduled to be completed by early 2015.
However, the project will not now finish until well into next year with work to complete it delayed until March 2017.
North Wales Conservative AM Mark Isherwood has raised concerns over the further delays.
He said: “Last October the project appeared nearly complete, with two lines of track in place and a lot of infrastructure done.
“Local rail users told me that at that time the Network Rail Project Engineer was saying that the work would be completed on time and on budget and passengers had expected trains to be using the two tracks during last winter.
“They further told me that work came to a stop when it was discovered that signalling cable needed replacement – something outside of the Network Rail budget for the job despite the £44m allocated by the Welsh Government.
“The delays have been incredibly frustrating for passengers who travel between Wrexham and Chester.”
He added: “Conclusion of the project will reduce inconvenience for passengers who otherwise have to wait at Wrexham for a train to clear the long section before the next one proceeds.
“Rail users have told me that the continuing delays are causing frustration and they are concerned that the benefits from this commissioning are unlikely to be released until later in 2017.
“I will be keeping a close eye on progress, ensuring that my constituents aren’t further let down.”
A Network Rail spokesman said: “We are delivering a project, funded by Welsh Government, to improve journeys between North and South Wales.
“We have been liaising with the train operators and local authorities to secure the required track access to deliver the final commissioning of the project, which has now been agreed.
“In spring 2017 the new signalling equipment will be commissioned and we will be completing work to increase the line speed.
“We will continue to update passengers, the local community and elected representatives of our progress as we work with our industry partners to reduce journey times and enable more trains to run between North and South Wales, as well as delivering significant safety improvements to four level crossings between Wrexham and Chester.”